Field of the Invention
The present invention relates to a light source apparatus and a projector including the light source apparatus.
Description of the Background Art
A light source apparatus provided in a projector according to the related art includes a red light source, a blue light source, an excitation light source for emitting excitation light in a blue wavelength bandwidth, a fluorescent light emitting source having a phosphor wheel to be rotatively driven by a motor, and a light source side optical system. An annular fluorescent light emitting region is provided on a disk-shaped metallic base material in the phosphor wheel of the fluorescent light emitting source. A reflection surface for reflecting light is formed in the fluorescent light emitting region, and a layer of a green phosphor for absorbing the excitation light in the blue wavelength bandwidth to emit fluorescent light in a green wavelength bandwidth is provided on the reflection surface. Both the fluorescent light turned from the layer of the green phosphor toward the reflection surface side and the excitation light turned toward the reflection surface without conversion into the fluorescent light are reflected by the reflection surface. However, the latter (the excitation light) is absorbed into the phosphor again and is thus converted into the fluorescent light. For this reason, many pieces of fluorescent light are emitted as green light from the layer of the green phosphor to the excitation light source side (for example, see Japanese Patent Application Laid-Open No. 2011-95388 (Page 14, FIG. 4).
The phosphor wheel of the light source apparatus disposed in the projector according to the related art is provided with the annular florescent light emitting region. For this reason, a phosphor material is annularly applied by utilizing a dispenser or the like in order to form the layer of the green phosphor on the disk-shaped metallic base material. When the phosphor material is applied annularly, however, an application start portion and an application end portion overlap with each other, and a thickness of the layer of the phosphor in the overlapping portion is different from thicknesses in the other portions. A quantity of the fluorescent light emitted through absorption of the excitation light subjected to irradiation into the phosphor is a sum of a fluorescent light part emitted directly and a fluorescent light part of reemitted light which is reflected by the reflection surface of the phosphor wheel. Therefore, if a difference is made in a thickness and a width of the layer of the phosphor, a total quantity of the fluorescent light is varied. As a result, there is a problem in that a luminance of the light source utilizing the fluorescent light is changed and a brightness of a image to be projected onto a screen is thus influenced (a brightness of the image is changed).